**Status.** Five SMALL-band trap/mechanism proposals and a four-region encounter-pressure map, not owner-approved canon, fixed geography, balance, or a complete campaign. The two-origin labels use the current alien-experiment/human-hospital story only as a replaceable hypothesis. Ordinary automatic fire, manual specials, journal pause, carried-property return, and persistent completed work follow the current rules; every quantity and placement remains proposed.

A mechanism exposes its cause before or with its first consequential action: a moving part, gauge, lit path, sound with a visual directional equivalent, or visible trigger volume. Quiet looking does not activate it unless it is visibly a gaze sensor. Capturing, changing a control, rewiring, cutting, or testing happens in world time. The journal freezes mechanisms, enemies, oxygen, projectiles, readiness, and action progress; it completes nothing and advances no timing window.

Each staged disable or reconfiguration names physical checkpoints. Damage alone does not cancel a stage; canceling, displacement from the control, or an occupied control can. Completed checkpoints persist; an unfinished stage is lost on withdrawal or death. Temporary timing states reset as stated below. Death returns everything still carried, leaves consumed, dropped, or installed property in its actual state, and shifts unbound geography. No mechanism grants a cache, extraction gate, sacrifice requirement, survivor result, route revelation, translation, or joining exception.

*Replaceable ancient-origin hypothesis.* A chamber built to orient test subjects around an unknown field now tilts its floor and swings two heavy ribs when unequal mass crosses its paired plates.

**Scene and read.** From the threshold, dust rolls toward one rib, two plate outlines brighten in sequence, and a suspended plumb cage leans before the floor moves. Crossing one plate starts a long, visible tilt; reaching equal load stops it. The effect displaces bodies and loose objects, may move the astronaut off a control, and changes which local ledge is walkable. It does not move station regions or erase a connection.

**Responses.** The player can time a crossing along the fixed handrail; place loose mass on the other plate; or complete two cutter-release checkpoints and pin one rib. A Vector Nozzle can push eligible loose mass onto a plate, while its recoil must be accounted for. Nozzle is an option, not a key. A strong combat rig may simply clear the room before solving its movement problem.

**Learning and state.** Plate order and the plumb cage let the player predict which side will descend in a later chamber. On alive withdrawal or death, an unpinned chamber returns to neutral; deliberately placed loose objects remain. Each completed release and pin persists, even if the room later has different neighbours; an unfinished release resets. The pin does not bind the room.

*Replaceable ancient-origin hypothesis.* Paired vessels alternately draw and expel local gas, perhaps once used to compare different forms of respiration.

**Scene and read.** A transparent vessel contracts, a three-beat indicator travels toward one grated lane, and frost forms there before suction begins. The lane increases suit drain and pulls loose debris toward the vessel; the opposite lane is quiet until the next cycle. Nothing silently removes a canister or changes its fill.

**Responses.** Wait behind hard structure and cross during the visible exchange; take the longer dry maintenance ledge; or hand-close two service caps, each a persistent checkpoint. Barrier Plate can stop carried debris as external impacts, and a Dynamo clamped to that Barrier may collect qualifying force events. The system never creates oxygen or charge merely because gas moved.

**Learning and state.** On later banks, indicator direction predicts which lane will draw next without translating adjacent script, supporting a shortcut or enemy lure. Withdrawal or death leaves completed caps closed; an incomplete cap returns to its prior position. Otherwise the bank begins the next expedition at its shown neutral phase rather than preserving a hidden timer. Death shifts its room normally; historical records reveal no new route.

*Replaceable human-hospital hypothesis.* A patient-routing vestibule closes one branch when its floor frame and wrist-reader register a transfer, now treating creatures and the astronaut as untrusted traffic.

**Scene and read.** Two destination lamps, a floor outline, and a shutter preview illuminate before the reader commits. Crossing the frame closes the previewed branch, opens the other, and sounds a local alert whose connected entrance is shown. The alert moves only eligible existing groups.

**Responses.** Observe the preview and choose which side to stand on; send a loose object or enemy across the frame from cover; or finish a baseline-cutter override before crossing. A visibly compatible service socket may accept a Fork Relay to keep both local outputs supplied, but only at an authored instance and at the cost of leaving the Fork installed. No part name decodes the destination marks.

**Learning and state.** Repeated lamp order can support a later prediction about which shutter a matching relay will close; disagreement remains a hypothesis. Occupancy and alarm readiness reset after withdrawal or death, but groups already moving do not vanish on withdrawal. Completed override stages persist, and a completed mechanical dog remains set through death. A Fork-powered state lasts only while the part remains installed and the fixture powered; installation persists, power need not. The vestibule gains no fixed post-death neighbour.

*Replaceable human-hospital hypothesis.* Rotating treatment arms sweep a bounded heat sheet across a ward while mobile shield panels once protected staff.

**Scene and read.** The arm locks into one of three visible detents, its next arc is painted on the floor, and shutters iris around the emitter before a heat sweep. The sweep damages exposed bodies and briefly blocks ordinary line of sight through its glare; it neither targets the player secretly nor makes sheltered enemies valid automatic targets.

**Responses.** Move between marked cool bays; push an eligible shield panel into the arc; or cut and lock the arm at a completed detent. Vector Nozzle can move a loose panel or shove a creature into the announced sweep. Barrier Plate has no assumed immunity to heat; it helps only if an instance identifies a physical impact it can intercept.

**Learning and state.** A locked detent stays locked across withdrawal and death. A completed first clamp remains cut even if the second is unfinished; the unfinished clamp resets. Otherwise withdrawal or death returns the carousel to a shown neutral detent, never an invisible mid-sweep. Its room can shift, making old cover records historical.

*Replaceable layered-origin hypothesis.* Human crash-cart rails were attached to an older conductive floor. Impacts on a charged rail now send one visible arc across nearby conductive bodies.

**Scene and read.** A rail rings when struck, floor seams light outward, and a rising meter names the bounded discharge area before the arc. A hit from a creature, loose bed, or the astronaut can arm it; the grid discharges once, then visibly recharges. It does not invent enemies or chain through an invalid target.

**Responses.** Walk the unlit ceramic strips and avoid striking the rail; cut two feed clamps and throw the breaker; or deliberately lure a crowd onto the seams and trigger the rail from cover. A Manual Trigger → Vector Nozzle can move eligible bodies or a bed onto the grid. Threat Sensor → Pulse Projector may automatically strike a valid nearby hostile, but it is not guaranteed to hit the rail. Arc Emitter follows its own target and readiness rules rather than inheriting the grid's chain.

**Learning and state.** The player can later reuse an enabled grid against a horde; disabling it trades that tool for safer travel. Charge and recharge phase reset on withdrawal or death. Each cut clamp persists, and a thrown breaker leaves the grid disabled through death. Reclosing it is a separate completed world action only where authored; death never repairs it.

These replaceable regions use the outline's provisional **four-region** SMALL band, not a fixed route or final count. After death, unbound adjacencies can change; only selected completed joins and mechanism states persist.

| Replaceable region | Local travel and contested-work rhythm | Ordinary / special pressure and candidate mechanisms | What it teaches |

|---|---|---|---|

| **Dock Collar and Cargo Turn** | Mostly readable route crowds; one occasional loud isolation job near a cued entrance. Detours trade oxygen for fewer bodies. | Pressers and one caller; a simple Triage Relay and a single-detent Carousel. | Warnings have causes; bypass, staged disable, and direct victory are all valid. A loose part can serve rig or infrastructure. |

| **Clinical Exchange** | Branching ward travel with short observation stops; caps and shutters create occasional contested work rather than every clue becoming defence. | Pressers, flankers, and a candidate Glass Siphon; Breath Banks, Triage Relays, and one Resuscitation Grid. | Oxygen pressure differs from damage, completed work shortens returns, and a routing signal predicts an operation without proving a translation. |

| **Ascension Works** | Open galleries alternate with narrow force rooms; safe-looking shortcuts demand local testing. Work is sparse but displacement can cost an unfinished stage. | Denser pressers plus candidate Bellback and Shutterback appearances; Phase-Balance chambers and stronger Breath Banks. | Hazards affect enemies too, cover changes automatic targeting, and observed cadence can be prepared for rather than stat-checked. |

| **Core Transfer Fringe** | Several objectives can be approached from whichever current adjacency exists; selective high-pressure mechanisms guard evidence or reusable infrastructure, not every path. | Mixed ordinary groups, callers, and one of the proposed special roles at a time; layered Resuscitation Grids, Carousels, and a composite relay instance. | Earlier signals combine into practical predictions. The player chooses safe disable, dangerous reuse, or overpowering combat while preserving capacity for findings. |

Population and placements may differ between expeditions. Clearing a crowd wins that local population for the expedition; no mechanism spawns a compensating elite. A group may arrive only through a readable route, perception cue, caller, or mechanism alert.

**Pressure gallery: overpower or understand.** In Ascension Works, pressers approach through a Phase-Balance chamber while a Breath Bank throws force-bearing debris across the control. Under a replaceable later **8 A** allowance, Threat Sensor → Pulse Projector supplies ordinary automatic fire, while Manual Trigger → Barrier Plate is the faced special; Dynamo is clamped to the Barrier, Capacitor stores qualifying impact charge, and its built-in manual release feeds Arc Emitter. The player faces the announced draw lane, catches debris and strikes, lets automatic fire thin the nearest valid targets, then manually releases Arc into the packed survivors. If the build clears them before the next cycle, it wins cleanly: no new wave or reduced reward appears, and the player completes the caps in quiet.

Another player needs none of those parts. They observe the three-beat light, use hard cover during suction, cross while the plate is neutral, and close one cap before withdrawing. That checkpoint persists. The journal permits comparison, but the bank does not advance and the cap does not close while paused.

**Sterile ward: create the angle or take the long way.** A Shutterback shelters pressers beside a Sterilization Carousel. A later **5 A** rig uses Threat Sensor → Pulse Projector for ordinary automatic fire and Manual Trigger → Vector Nozzle as a faced special. The player waits for the shown cool detent, manually shoves Shutterback sideways, and exposes the crowd; automatic fire now has valid targets, while the next announced sweep catches bodies left in its arc. A strong execution can empty the ward without replacement pressure.

Alternatively, the player records the detent order from cover, takes the longer maintenance bay, and cuts the first carousel clamp while enemies remain elsewhere. Or they ignore the mechanism and spend oxygen on a different current connection. The journal can hold the frozen view for thought, but cannot rotate the arm, finish the record, reveal an unwalked route, or interpret its marks.

**This first-pass package:** five family rules, a four-region pressure map, two encounter traces, and persistence checks. Planning envelope: Systems authoring **6–10 role-hours**, focused review **3–5**, response **2–4**; **11–19 total**. It maps to the outline's trap and encounter allowances without recounting creature, equipment, survival, combat, or interface work.

**Later finite SMALL inventory:** author the outline's proposed **12 placed mechanism instances** across the five families, plus four detailed regional pressure briefs and their cross-instance dependency check: Systems **24–40 author role-hours**, focused review **6–10**, response **3–5**; **33–55 total**. Each instance would specify geometry, warning, stages, state transitions, alternatives, and its current-region placement. This excludes creature roster/behaviour, equipment definitions, interface and accessibility cue design, survivor scenes, language-chain writing, reusable room-module and objective authoring, implementation, assets, numerical tuning, simulation, and playtesting. A room, scene, clue, or set-piece hosting a mechanism is one cross-listed content unit, not additive labor in every category. TARGET/STRETCH remain unestimated.

Later owner-authorized implementation and observation must test readability under horde density, whether five families remain distinct, whether bypass and overpower routes are viable, whether reusable hazards feel discovered rather than scripted, and whether death shifts preserve understanding without creating route confusion. This paper design establishes none of those outcomes.